Self-Assembly of 2D Nanosheets into 1D Nanostructures for Sensing NO₂

Ultrathin 2D nanosheets are one of the appealing building blocks for constructing self-assembled nanostructures. Herein, a facile, fast, and general solvent-mediated route for the high-yield and large-scale self-assembly of ultrathin 2D nanosheets into 1D nanofibers and nanorings is reported. Solution-dispersed graphene oxide (GO), MoS₂, TiS₂, and TaS₂ nanofibers with lengths of several tens of micrometers and diameters of 20-50 nm are formed via the self-assembly of their corresponding single-layer nanosheets by simply vibrating their tetra-hydrofuran suspensions under vortex for 1 min at room temperature. Interestingly, by simply changing the solvent from tetrahydrofuran to acetone, nanorings with diameters of 200-500 nm can be obtained via a similar process. As a proof-of-concept application, the reduced GO (rGO) nanofibers obtained by thermal reduction of the GO nanofibers are used as the channel material to fabricate electronic gas sensor, showing good sensitivity (with a detection limit of ≈75 ppb) and selectivity toward NO₂. The simple assembly strategy can be used to assemble other ultrathin 2D nanomaterials into 1D nanostructures for various promising applications.